I'm not sure if it was intentional, but there seem to be some slight issues with the combat system.

When becoming immortal, I chose to become a vampire because the ability to heal wounds sounded interesting to me - especially for boss battles in the level 52+ areas. However, I have found that your healed wounds are totaled at the end of a battle. For me, this is a little immersion breaking, but the bigger issue is when a character dies because wounds sustained during combat that have been "healed" have not been tallied. While I can understand if this was intentional to prevent vampire immortals from being overpowered, perhaps the description should be changed from "A good chance to drain blood with each hit, to potentially heal you of a wound instantly."

I have also found that the at least the Celerity buff (+15 AR) wears off before it notifies you, meaning that when you get notice that the effect has worn off you just finished fighting a monster without its benefit. While I haven't been able to check, I would guess it is the same for all of the active skills.